1. Field of the Invention
The present invention relates to a page layout technique for rearranging a drawing object such as a figure or a character string contained in document data that has been laid out.
2. Description of the Related Art
Techniques to suppress copying of a document that is required to guarantee authenticity are discussed in Japanese Patent Application Laid-Open No. 2001-197297 and Japanese Patent Application Laid-Open No. 2001-238075. In the techniques discussed in the Laid-Open No. 2001-197297 and the Laid-Open No. 2001-238075, when document data created with a computer is output in paper, an image called a copy-forgery-inhibited pattern is superimposed on the document data and output. When such a print document with the copy-forgery-inhibited pattern attached thereto is copied, a copy product on which a latent image remains and a copy-forgery-inhibited pattern background image is lost can be obtained.
The copy-forgery-inhibited pattern includes large dots (concentrated dots) that can be detected by an image scanner and small dots (dispersed dots) that cannot be detected by the image scanner. Hereinafter, an image that is formed of the large dots and remains (is reproduced) after copying a print product, is referred to as a latent image. An image that is formed of the small dots that disappear (is not reproduced) after copying the print product, is referred to as a copy-forgery-inhibited pattern background image. Further, an area that includes a latent image (latent image area) and a copy-forgery-inhibited pattern background image (copy-forgery-inhibited pattern background area) is referred to as a copy-forgery-inhibited pattern image (copy-forgery-inhibited pattern area).
Meanwhile, a technique to save the number of output sheets by closing up blank areas in a page is discussed in Japanese Patent Application Laid-Open No. 2000-318230.
In FIG. 10, a page 1003 is a print product on which a copy-forgery-inhibited pattern image is attached. A drawing object 1001 is, for example, a character that is not related to the copy-forgery-inhibited pattern image. In the drawing, reference numeral 1002 denotes a latent image and reference numeral 1000 denotes a copy-forgery-inhibited pattern background image. When the print product of the page 1003 is copied, a copy product 1004 is formed. On the copy product 1004, the drawing object 1001 and the latent image 1002 remain. However, the copy-forgery-inhibited pattern background image 1000 is lost. As described above, on the print product of the document data on which the copy-forgery-inhibited pattern is attached, the relationship between the drawing object such as the image and the character that is not related to the copy-forgery-inhibited pattern image, and the drawing object that forms the copy-forgery-inhibited pattern area is similar to a relationship between a front object and a background object. Accordingly, it is in effect possible to regard the copy-forgery-inhibited pattern area as a blank area. However, in the known techniques, an area where no object exists is regarded as the blank area. More specifically, in the copy-forgery-inhibited pattern image area that can be in effect considered as the blank area, a latent image area and a drawing object for forming a copy-forgery-inhibited pattern background image are contained. Accordingly, it has not been possible to recognize the above-described copy-forgery-inhibited pattern area as the blank area.
For example, in Japanese Patent Application Laid-Open No. 2000-318230, a line on which no object is laid out is specified as a blank line. By deleting the blank line and re-laying out an object in a succeeding page, the number of sheets is reduced. More specifically, in the technique discussed in Japanese Patent Application Laid-Open No. 2000-318230, the copy-forgery-inhibited pattern area that can be in effect regarded as a blank area is not considered the blank area. Accordingly, the number of sheets may not be saved.